Long-term X-ray variability and state transition of GX 339-4
Abstract
With extensive monitoring data spanning over 30 years from Vela 5B, Ariel 5, Ginga, Compton Gamma Ray Observatory, Rossi X-ray Timing Explorer and BeppoSAX, we find evidence for long-term X-ray variability on time-scales ~190-240d from the black hole low-mass X-ray binary system GX339-4. Such variability resembles the outburst cycle of Z Cam-type dwarf novae, in which the standard disc instability model plays a crucial role. If such a model is applicable to GX339-4, then the observed variability might be due to the irradiation of an unstable accretion disc. We show that within the framework of the X-ray irradiation model, when the accretion rate exceeds a critical value, GX339-4 enters a `flat-topped' high/soft state, such as seen in 1998, which we suggest corresponds to the `standstill' state of Z Cam systems.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2002
- DOI:
- 10.1046/j.1365-8711.2002.05022.x
- arXiv:
- arXiv:astro-ph/0110039
- Bibcode:
- 2002MNRAS.329..588K
- Keywords:
-
- ACCRETION;
- ACCRETION DISCS;
- BLACK HOLE PHYSICS;
- BINARIES: CLOSE;
- STARS: INDIVIDUAL: GX339-4;
- X-RAYS: STARS;
- Astrophysics
- E-Print:
- 11 pages, 5 figures, accepted for publication in MNRAS